1. Field of the Invention
The present invention relates to an image forming apparatus with a supply device that feeds a recording medium placed on an elevatable tray toward a transfer area where a toner image is transferred onto the recording medium.
2. Description of Related Art
A conventional image forming apparatus with a supply device as described above is described in, for example, Japanese Patent Laid-Open Publication No. 2003-165650. This supply device has a light shield attached to a lift plate (elevating plate) that supplies a recording medium (e.g., paper) to a feed position by vertically changing the position of the recording medium. Three detection sensors for performing detection on the basis of whether irradiation light is blocked or not are vertically arranged in positions where the light shield can block irradiation light by the position of the lift plate being changed. The remaining quantity of sheets of recording medium that corresponds to the position of the lift plate is detected on the basis of a combination of the results of detection by the detection sensors.
However, to accurately detect the remaining quantity of sheets of recording medium, the supply device requires a number of detection sensors to be vertically arranged at short intervals.